The invention relates to a method for controlling or regulating a folder of a printing press. Furthermore, the invention relates to a printing press having a folder.
Folders of printing presses serve to form folds on printed printing materials, a web-shaped printing material customarily being guided first of all through what is known as a folding former for fold formation according to the prior art, in order for a longitudinal fold to be formed in this way on the web-shaped printing material which has not yet been severed. Starting from the folding former, the web-shaped printing material is transported via several pull rolls in the direction of a cutting knife cylinder and a folding blade cylinder which interacts with the cutting knife cylinder, copies which are moved in the direction of a folding jaw cylinder with the aid of a folding blade cylinder being severed from the web-shaped printing material on the cutting knife cylinder. The copies which are severed from the web-shaped printing material on the cutting knife cylinder and are moved in the direction of the folding jaw cylinder by the folding blade cylinder are transferred to the folding jaw cylinder with formation of a first crossfold by the folding blade cylinder. Further, second crossfolds can be formed between the folding jaw cylinder and a gripper cylinder which interacts with the latter. The copies which have been provided in this way with a longitudinal fold and crossfolds can then be provided with second longitudinal folds while still in the region of a folding table which is connected behind the gripper cylinder, the second longitudinal folds running parallel to the longitudinal fold which was formed in the folding former.
If the fold formation is to be checked according to the prior art, a folded printed copy is removed from a printing press, unfolded and examined in the unfolded state by a printer. If the printer notices here that folds run obliquely, actuators for the folding former and/or the folding blade cylinder and/or the folding jaw cylinder and/or the folding table are adjusted manually by the printer in such a way that the desired fold is formed on subsequent printed copies. Here, the procedure is purely empirical according to the prior art, with the result that there are no reproducible results during the adjustment of the folder which is performed by the printer.
Proceeding from this, the present invention is based on the problem of providing a novel method for controlling or regulating a folder, and also of providing a printing press with a folder.
According to the invention, setpoint fold values are generated on the basis of prepress stage data, printed copies being measured in the folded and/or partially folded state in order to determine actual fold values, the actual fold values which are determined in the process being compared with the corresponding setpoint fold values, and, as a function of this comparison, the folder being set automatically in such a way that the actual fold values correspond to or are approximated to the setpoint fold values in subsequent printed copies.
In the context of the present invention, it is provided for the first time to regulate or control a folder on the basis of setpoint fold values which are generated from prepress stage data. For this purpose, printed copies are measured in the folded and/or partially folded state in order to determine actual fold values, the actual fold values which are determined in the process being compared with the setpoint fold values which are based on the prepress stage.
As a function of this comparison, actuating signals are determined for the actuators of the folder, in order to set the folder automatically in this way. As a result, it is possible to achieve reproducible results during the setting of folders. Furthermore, the method according to the invention can run fully automatically, with the result that an intervention by a printer is unnecessary.